[release-2.7] Simplify isEmittedFile check instead of iterating through all source files

src/compiler/program.ts

@@ -2351,9 +2351,30 @@ namespace ts {
                 return false;
             }
 
-            return forEachEmittedFile(getEmitHost(), ({ jsFilePath, declarationFilePath }) =>
-                isSameFile(jsFilePath, file) ||
-                (declarationFilePath && isSameFile(declarationFilePath, file)));
+            // If this is source file, its not emitted file
+            const filePath = toPath(file);
+            if (getSourceFileByPath(filePath)) {
+                return false;
+            }
+
+            // If options have --outFile or --out just check that
+            const out = options.outFile || options.out;
+            if (out) {
+                return isSameFile(filePath, out) || isSameFile(filePath, removeFileExtension(out) + Extension.Dts);
+            }
+
+            // If --outDir, check if file is in that directory
+            if (options.outDir) {
+                return containsPath(options.outDir, filePath, currentDirectory, !host.useCaseSensitiveFileNames());
+            }
+
+            if (fileExtensionIsOneOf(filePath, supportedJavascriptExtensions) || fileExtensionIs(filePath, Extension.Dts)) {
+                // Otherwise just check if sourceFile with the name exists
+                const filePathWithoutExtension = removeFileExtension(filePath);
+                return !!getSourceFileByPath(combinePaths(filePathWithoutExtension, Extension.Ts) as Path) ||
+                    !!getSourceFileByPath(combinePaths(filePathWithoutExtension, Extension.Tsx) as Path);
+            }
+            return false;
         }
 
         function isSameFile(file1: string, file2: string) {

src/server/server.ts

@@ -33,6 +33,7 @@ namespace ts.server {
     const os: {
         homedir?(): string;
         tmpdir(): string;
+        platform(): string;
     } = require("os");
 
     interface NodeSocket {
@@ -824,8 +825,9 @@ namespace ts.server {
     const logger = createLogger();
 
     const sys = <ServerHost>ts.sys;
+    const nodeVersion = getNodeMajorVersion();
     // use watchGuard process on Windows when node version is 4 or later
-    const useWatchGuard = process.platform === "win32" && getNodeMajorVersion() >= 4;
+    const useWatchGuard = process.platform === "win32" && nodeVersion >= 4;
     const originalWatchDirectory: ServerHost["watchDirectory"] = sys.watchDirectory.bind(sys);
     const noopWatcher: FileWatcher = { close: noop };
     // This is the function that catches the exceptions when watching directory, and yet lets project service continue to function
@@ -980,8 +982,9 @@ namespace ts.server {
     };
 
     logger.info(`Starting TS Server`);
-    logger.info(`Version: ${versionMajorMinor}`);
+    logger.info(`Version: ${version}`);
     logger.info(`Arguments: ${process.argv.join(" ")}`);
+    logger.info(`Platform: ${os.platform()} NodeVersion: ${nodeVersion} CaseSensitive: ${sys.useCaseSensitiveFileNames}`);
 
     const ioSession = new IOSession(options);
     process.on("uncaughtException", err => {